The present invention relates to stationary bench or standard mounted abrasive belt machines of the type wherein an operator of the machine normally presents an article to be ground or finished to an abrasive belt driven by the machine.
Prior commercially available machines of which I am aware appear to be of two general types. In a first type of machine, a post is fixed to upstand from a workbench and removably attached to the casing of a portable hand-operated belt grinder, such as for example grinders of the type disclosed in commonly assigned U.S. Pat. Nos. 3,823,513 and 4,368,597. The post is made adjustable, so as to allow the whole of the belt grinder to be tilted vertically as required to position its contact arm, and thus that portion of the abrasive belt trained thereabout, in a desired position convenient for use by an operator of the machine. A drawback of this type of machine is that belt width is limited by the size of the drive and tension rollers permanently built into the portable machine.
In a second type of machine, a stationary base or housing supported on a bench top or pedestal serves to mount belt drive and tension control rollers and means to removably support a contact arm of the type shown for instance in U.S. Pat. No. 3,823,513, whereby to permit an abrasive belt to be trained about the drive and tension control rollers and an idler or contact roller carried by the contact arm. While this type of machine is adapted to accommodate a wide range of belt widths by the expedient of changing the size of the contact arms fitted thereto, such machine has the drawback that each contact arm, and thus that portion of the belt trained thereover, is required to be maintained in a fixed position and not adapted to be adjusted for the convenience of an operator.